In ecology, a limiting factor is a factor that limits the growth, distribution, or abundance of a species in a particular environment. Limiting factors can be biotic (related to living organisms) or abiotic (related to non-living factors).
Some common examples of biotic limiting factors include competition for resources such as food, water, and space, and predation by other species. Abiotic limiting factors can include temperature, moisture, light, soil type, and other physical and chemical conditions of the environment.
Limiting factors can operate at different levels in an ecosystem. For example, a limiting factor at the individual level might be the availability of food or water for a particular species, while a limiting factor at the population level might be the availability of suitable habitat.
Understanding limiting factors is important for predicting the distribution and abundance of species in a particular environment and for informing conservation efforts to protect and preserve species and their habitats.
Limiting factors vary from ecological factors because ecological factors are any environmental conditions that influence the life of one or more organisms. In contrast, limiting factors are those factors or variables in an environment capable of restricting the growth, abundance, and distribution of organisms in an ecosystem. For example, limiting factors refer to those that limit the population’s size and slow it down or stop it from increasing.
The characteristics of the limiting factors have been listed as follows:
They need to be in sufficient amounts in the ecosystem, as indicated by the name.
They are any conditions that approach or exceed an organism’s or group’s tolerance limit.
If any of the limiting factors changes, the populations of animals or plants also can change along with it.
They limit the growth or distribution of an ecosystem.
They can be either physical or biological factors that are identified by the increase or decrease in the development or distribution of a population.
They can be single or a group of related factors.
There can be single or many limiting factors at once in an ecosystem, affecting the ecology of both plants and animal species in the ecosystem.
They restrict the number of individuals in a population. As a result, they can affect more than one population in a community.
Limiting factors are mainly of two types: abiotic factors and biotic factors.
Abiotic factors: This includes non-living things like shelter, climate, temperature, altitude, water, space, soil chemistry, sunlight, fire, and natural disaster. For example, water is essential for life, and animals have different adaptations to store enough water in their body. Animals either liver in or outside water. They drink water to fulfill their basic needs. In desert plants, the plants have adapted modifications in their body to store water. Likewise, sunlight provides energy to all living organisms; the plants convert it into heat energy and food energy, and the animals consume the plants and take up the sunlight. Similarly, the climate is one of the solid abiotic factors influencing plants’ and animals’ growth.
Biotic factors: This includes living things with several plants, animals, decomposers, parasites, disease-causing agents, food, mates, and competition among organisms. The biotic or biological factors involve interactions between the organisms in the form of predation, competition, parasitism, and herbivory. Predation occurs when one species is made food by another species, like the preying of rabbits upon the grasses and the preying of the hawks on the rabbits. If the population of the predator increase, then the people of the prey decrease, and vice-versa. When resources become scarce, competition occurs, direct or indirect. Direct competition occurs when a group of individuals fights with each other for a single help. For example, elephants fight for a mate. Indirect competition occurs when one species indirectly affects another species by emptying up the resources. For example, deer eat up all the grasses on the forest floor, leaving nothing for other herbivorous animals. Competition can result in decreasing one population, whereas the increase of a different population or shift within a population. Predation occurs in organisms that cause disease. The higher the size of the people, the more will be the chance of disease transmission.
So, limiting factors can be any biotic or abiotic factor restricting the size, number, or reproduction of organisms in an ecosystem. Limiting factors can be simply understood as a lack of a resource preventing something from growing. For example, in an aquatic ecosystem, if there is not enough space for the fish, then, in this case, space is a limiting factor. Similarly, if food becomes scarce in the same water, it results in competition among the fish species for food. Thus, many different limiting factors in an ecosystem may highly influence the populations of plants and animals. Let’s take an example of a small fish aquarium. The limiting factors here can be the size of the bowl, the amount of water or the temperature of the surroundings, any of these can be responsible for the number and the growth of fish in that type of ecosystem. Finally, the limiting factors identify the carrying capacity of a habitat, which is its capacity to support the maximum size of the population. When the limiting factors become excess or if any of them depletes, this can lead to degradation and even habitat destruction.
Factors affecting the carrying capacity
Factors increasing the carrying capacity include changing climate or other environmental factors, technological efficiency advances, decreased body size, and resource demand.
Factors decreasing the carrying capacity: changing climate or other environmental factors, environmental degradation, depletion of nonrenewable resources, and introduction of a new competitor.
The limiting factors can be density-dependent limiting factors or density-independent limiting factors.
- Density-dependent limiting factors: They depend upon the number of living organisms. For example, in an ecosystem, the amount of food available for each organism depends on the number of organisms in the ecosystem. The density-dependent limiting factors depend upon the population size. They limit population growth and can vary with the population size. The living factors can be density-dependent because the size of a population influences its number. These factors operate powerfully in the ecosystem when the population becomes more considerable. So, the following come under these types of elements:
- Availability of food and water
- Competition
- Predation
- Parasitism and disease
- Density-independent limiting factors: They do not depend upon the number of the living organism. They are limitations to population growth that are not dependent on population density. For example, the amount of precipitation does not depend on the number of organisms in the ecosystem. So, the following come under these types of factors:
- Pollution
- Extreme weather
- Seasonal changes
- Catastrophic events like earthquakes, volcanoes, tsunamis, etc.
A habitat carrying capacity, or the maximum number of individuals of a population that a habitat can support, is determined by limited limiting factors.
Limiting factors are environmental factors that determine the growth of populations.
Whether density-independent or density-independent limiting factors, major changes to any population can create an imbalance between the individuals and their environment, allowing the species to have more individuals than the earth can support.
Blackman’s law of limiting factors
According to this law, a biological process is carried out by many factors, but the limiting factor controls it.
Examples of photosynthesis, respiration, etc. In photosynthesis, the required raw materials are water, carbon dioxide, sunlight, etc. If one of them becomes limited, then the rate of photosynthesis becomes affected.
Liebig’s law of minimum
The German Organic Chemist Justus Von Liebig 1840 came up with the idea that ‘The weakest link in the ecological chain of requirements may control organisms.’ This idea became later known as ‘Liebig’s law of the minimum.’ Liebig’s law is also known as the barrel concept or barrel theory. Liebig used the image of the barrel with unequal steps to show how elements in the shortest supply limit plant growth.
In the barrel image, the water is leaking from the shortest steps; the most straightforward step limits the barrel’s capacity and can only be increased by lengthening the phase. When the stage is lengthened, another step becomes limiting in nature. So, Liebig’s law states, “Yield is proportional to the amount of the most limiting nutrient, whichever nutrient it may be. If one growth factor/ nutrient is deficient, plant growth is limited, even if all other vital factors/ nutrients are adequate. Plant growth is improved by increasing the supply of the deficient factor/ nutrient”.
This law implies that the least favorable amount of essential nutrients and environmental factors are required for the average growth and reproduction of an organism. If the element or nutrient is depleted below the necessary minimum, then either the organism grows abnormally or fails to produce.
Shelford’s law of tolerance
It is the modification in Blackman’s law and Liebig’s law. According to this law, the rate of any biological process is affected not only by the limiting factors but also by the abundance of those factors; according to a study of Shelford on the environmental influences on plants and animals, not only too little of a substance limit the presence or success of an organism but also too much. So, it can be concluded that the organisms live within a range of too much (critical maximum) and too little (required minimum). This range between the critical maximum and necessary minimum is known as the limit of tolerance. Before this range is crossed on either side and the limits of tolerance are reached, there is a zone of physiological stress. Beyond this zone, if the organism is exposed for a considerable time, it would be dead. Just before the zone of physiological stress, there is a zone of marginal safety during which the activities are adjusted to face the limit of tolerance. For example, in photosynthesis, if a low concentration of carbon dioxide affects the rate of photosynthesis, then the abundance of carbon dioxide also affects the rate of photosynthesis. Thus, many factors inhibit the absorption of other essential factors that stop the growth of biological processes.
Thus, combining the law of minimum and the law of tolerance provides the concept of limiting factors. The successful growth of an organism in an ecosystem depends upon a complex of conditions. When certain changes are made in these conditions, the factor or group of factors which approach or exceed the limit of tolerance for an organism or a group of organisms can be called the limiting factor.
What are 5 limiting factors in an ecosystem?
The five limiting factors in an ecosystem are:
Competition: When the population increases, the demand of food increases as well. Since food is a limiting resource, the organisms start competing for it.
Predation: Removal of predators can disturb the balance of natural, biotic, cycle of predators and prey. In some cases, the prey animals increase highly exceeding the carrying capacity of ecosystems and causing environmental damage.
Parasitism and disease: They can highly alter the population size. A disease can spread quickly through a larger population impacting the number of individuals within the population more than it would in a smaller, more widely dispersed population.
Drought and other climate extremes: They can aid in the growth of the pathogens or insect populations.
Human disturbances: Density dependent limiting factors like decreased availability of space due to deforestation is a global issue, which causes decline and extinction in many population. Resource scarcity caused due to overexploitation by human beings causes intraspecific and interspecific competition within and between populations,
Why are limiting factors important in an ecosystem?
The study of the limiting factors help the ecologists in studying the complex interactions occurring in the ecosystem.
The ecologists can discover the probable weak links and focus on those environmental conditions which are most likely to be critical or limiting.
Limiting factors matter as they affect the carrying capacity of the mosquito’s habitat. Carrying capacity is the number of individuals that a habitat can sustain with the resources available in it.
The study of limiting factors in population ecology helps to understand how fast or slow and high or low a population actually grows, what’s keeping their growth in check.
What are the types of limiting factors?
The population ecology groups the limiting factors into two different categories: density dependent limiting factors and density independent limiting factors. It helps to know whether a population growth rate is being controlled by how many individuals are or whether it is being controlled by something else. Limiting factors matter as they affect the carrying capacity of the organism’s habitat. Carrying capacity is the number of individuals that a habitat can sustain with the resources available in it.
The type of limiting factors have been explained by taking the example of the West-Nile virus outbreak (mosquito-borne illness) in Dallas, Texas in the summer of 2012.
Density dependent limiting factors: It occurs only when the population density reaches a certain level. Density dependent limiting factors are those which inhibit the growth because of the environmental stress caused by a population size. E.g.: there may not be enough food, water and space to provide accommodation to everyone. There may be so many individuals, when a nearby predator population explodes, this helps keep the population in check. Disease can also be a density dependent limiting factor. Lots of individuals living in close residents can spread infection. If the explosion of the mosquito population took place along with the Mexican free-tailed bats (the official flying mammal of the Texas state) which feed upon the mosquitoes, this can be a density dependent limiting factor. More mosquito population leads to more number of bats which results in fewer number of mosquitoes. When density dependent limiting factor starts to increase and limit the population growth, this means the habitat’s carrying capacity has been reached.
Density independent limiting factors: It occurs due to unusual weather or natural disasters like flood and fires and human activities like clear-cutting of forest or river damn. Density independent limiting factors have nothing to do with how many individuals there are and how dense the population is. The density independent limiting factors can be understood in terms of some catastrophe like volcanic eruption, a heavy monsoon or Chernobyl explosion. E.g. in 2013, there was a huge thunderstorm in Dallas every day for three months which washed away the clutches of mosquito eggs hanging out in the stagnant waters, so the number born became substantially smaller. The temperature too became unseasonably cold throughout the summer which dropped down the rate of mosquito’s growth. There are many more situations that could lead to a population either reaching its carrying capacity or collapsing because of external factors. Here, comes the role of population ecologists to figure out what those factors are.
What are the 2 types of limiting factors?
There are mainly 2 types of limiting factors: Density dependent limiting factors and Density independent limiting factors.
What are 4 examples of limiting factors?
The four examples of limiting factors are temperature, space (shelter), food and mates. This can be understood by the taking example of the condition of 2011 prior to the West Nile virus epidemic in 2012 at Dallas, Texas which occurred in the summer of 2012. In 2011, something was keeping their growth in down i.e. limiting factors which a mosquito needs to live and reproduce successfully. But, after a year, in 2012, they became widespread throughout the state due to the following reasons:
Mosquitoes could not run out of food i.e. fresh blood meal of vertebrates as Dallas is a densely populated city.
As mosquitoes are ectothermic, they are active in warm temperature. Texas is a hot area and the winter of 2011-2012 was pleasantly warm, even the summer of 2012 was too hot, which helped the mosquitoes speed up their life cycle.
Female mosquito mate with the male mosquitoes who gathered into a mosquito cloud at dusk every night during the mating season.
– Mosquitoes need to lay their eggs in stagnant water, the larvae cannot sustain if the rainwater flushes the little puddle of water they have been living in. Dallas observed a severe drought in the summer of 2012 and there were lots of pockets of stagnant water around which aid in the growth of plenty West Nile- infected mosquitoes.
Therefore, in 2011, the population of the mosquitoes were not so high due to the limiting factors like constraints of temperature, space (shelter), food and mates.
In the human civilization, when we look at the past trends, the human population grew very slowly. There were many limiting factors which made the human population remain low. The examples of such limiting factors are:
1. The food resources were not easily available everywhere.
2. The diseases flourished in most of the places when the epidemic struck a community due to the lack of health services.
What is the limiting factor principle?
According to Leibig’s law of minimum, the growth of a biological process is affected by the limiting factors while their abundance doesn’t affect the growth rate of that biological process. The central concept of the Liebig’s law of minimum can be understood in these three points:
An organism must have all the necessary materials which are required for growth and reproduction to occur and survive in a given situation.
Under ‘steady-state’ conditions, the essential materials available in amounts most closely approaching the critical minimum needed will tend to be the limiting one (the growth is not determined by the total resources available, but by the scarcest resource (limiting factor).
The law of minimum is not applicable under ‘transient state’ conditions.
According to this law, growth is regulated by the limiting factors i.e. the resources in scarcity but not in abundance. For the organisms and the overall ecosystem to be healthy factors such as food, air, space, nutrients, etc. must be available. The limiting factors are those factors in an ecosystem that can lower the population growth rate. This includes low food supply and lack of space. The limiting factors can lead to decrease in birth rate, increase and cause of immigration and extinction.
The Liebig’s law was given by the Justus Liebig in 1840. He identified that the production of crops was not only limited by the nutrients needed in huge quantities but by some raw materials needed in minute quantities but in very scarce. The Liebig’s law has been found to be started from this statement, ‘Growth of a plant depends on the amount of foodstuff which is presented to it in minimum quantity.
Modern Review of Liebig’s Law
Taylor explained that ‘the function of an organism is controlled or limited by essential environmental factor or combination of factors presented to it in the least favorable amount’.
Odum restricted the Liebig’s law of minimum to chemical materials like oxygen, phosphorous, etc.
Subsidiary principles of Liebig’s law
There are two subsidiary principles:
Subsidiary principle 1:
Liebig’s law of minimum is strictly applicable under steady state conditions. When the average inflow of energy and materials balance the outflow in annual cycles.
The best example of this is the carbon dioxide as the limiting factor in the lake ecosystem. The productivity is in equilibrium with its rate of supply coming from the decay of organic matter. The light, nitrogen, etc. are present in excess. If the amount of carbon dioxide is increased by external factors like storm, then the rate of production would change and becomes dependent on other factors. So, there is no steady state and the reaction depends on the concentration of all constituents present. The rate of production would change until there comes another limiting factor. Then, once again, the system will be operating at the rate controlled by the law of minimum.
Subsidiary principle 2:
The factor interaction is the second important consideration. The high concentration or availability of some substance or the action of some factor may modify the rate of utilization of a factor which is limiting. Example, when strontium is abundant in molluscs, they are able to substitute calcium to a particular extent in their shells.
Limitations of Liebig’s law:
– Liebig only studied the nutrients and the effects of nutrient deficiency.
– Liebig did not take into consideration the study of positive and negative synergism. Synergism is the result of an interaction of two or more factors so that the combined effect is greater than the sum of their separate effects.